UNSETENV(3) Library Functions Manual UNSETENV(3)

NAME

unsetenv — remove an environment variable

SYNOPSIS

[CX]
#include <stdlib.h>

int unsetenv(const char *name);

DESCRIPTION

The unsetenv () function shall remove an environment variable from the environment of the calling process. The name argument points to a string, which is the name of the variable to be removed. The named argument shall not contain an ‘=’ character. If the named variable does not exist in the current environment, the environment shall be unchanged and the function is considered to have completed successfully.

The unsetenv () function shall update the list of pointers to which environ points.

The unsetenv () function need not be thread-safe.

RETURN VALUE

Upon successful completion, zero shall be returned. Otherwise, -1 shall be returned, errno set to indicate the error, and the environment shall be unchanged.